主题：美国军方用孤儿院的少女种植梅毒做实验， 政府正式道歉 -- CaoMeng

Marta Orellana, 74, a victim of the US syphilis trial when she was nine. 'They never gave me a chance to say no,' she says. Photograph: Rory Carroll for the Guardian

Marta Orellana says she was playing with friends at the orphanage when the summons sounded: "Orellana to the infirmary. Orellana to the infirmary."

Waiting for her were several doctors she had never seen before. Tall men with fair complexions who spoke what she guessed was English, plus a Guatemalan doctor. They had syringes and little bottles.

They ordered her to lie down and open her legs. Embarrassed, she locked her knees together and shook her head. The Guatemalan medic slapped her cheek and she began to cry. "I did what I was told," she recalls.

Today the nine-year-old girl is a rheumy-eyed 74-year-old great-grandmother, but the anguish of that moment endures. It was how it all began: the pain, the humiliation, the mystery.

It was 1946 and orphans in Guatemala City, along with prisoners, military conscripts and prostitutes, had been selected for a medical experiment which would torment many, and remain secret, for more than six decades.

The US, worried about GIs returning home with sexual diseases, infected an estimated 1,500 Guatemalans with syphilis, gonorrhea and chancroid to test an early antibiotic, penicillin.

"They never told me what they were doing, never gave me a chance to say no," Orellana said this week, seated in her ramshackle Guatemala City home. "I've lived almost my whole life without knowing the truth. May God forgive them."

The US government admitted to the experiment in October when the secretary of state, Hillary Clinton, and the health secretary, Kathleen Sebelius, issued a joint statement apologising for "such reprehensible research" under the guise of public health. Barack Obama phoned his Guatemalan counterpart, Alvaro Colom, to say sorry too.

Susan Reverby, a professor at Wellesley College in the US, uncovered the experiment while researching the Tuskegee syphilis study in which hundreds of African American men were left untreated for 40 years from the 1930s.

The Guatemalan study went further by deliberately infecting its subjects. Not only did it violate the hippocratic oath to do no harm but it echoed Nazi crimes exposed around the same time at the Nuremberg trials.